const runtime.traceEvGoBlockGC

2 uses

	runtime (current package)
		mgcmark.go#L619: 	goparkunlock(&work.assistQueue.lock, waitReasonGCAssistWait, traceEvGoBlockGC, 2)
		trace.go#L65: 	traceEvGoBlockGC         = 42 // goroutine blocks on GC assist [timestamp, stack]